Another perspective on Jellyfish Stings

Treatment

The treatment of all jellyfish stings is controversial and the scientific literature in some cases is inconclusive or conflicting.  For some jellyfish stings hot water is recommended while in other species ice packs.  For some species vinegar (acetic acid) and in others  baking soda slurry (sodium bicarbonate) is recommended to inactivate the nematocytes.[8]  

Vinegar is no longer recommended by the Red Cross for most jellyfish stings in U.S. waters, as there have been some studies that showed increased release of venom with its use.[9]  Several studies found vinegar (acetic acid) increased nematocyst discharge in mauve stingers but seawater did not.[10,11]  An in vitro study (a study done in the  laboratory) conversely found that vinegar did reduce nematocyst discharge in mouth arm nematocysts.[12].  That same study found that 1% lidocaine, 70% ethanol, and 20% ammonia in vitro reduced nematocyst discharge, but as is not atypical another study found the exact opposite, that ammonia activated the nematocysts.[11]  It has also been found that calcium ions may be an important part of nematocyst activation and gadolinium which blocks cellular calcium channels was found to block nematocyst discharge in one study, but had no effect in another.[3,11,13]  

The Maltese government has a handout for jelly fish treatment that recommends a baking soda (sodium bicarbonate) slurry (a mixture of 50% commercial baking soda and 50% seawater) for mauve stinger jellyfish stings.[14]  Baking soda been found to help inactivate nematocysts in sea nettle stings, but I was unable to find another reference to recommend this treatment for this mauve stinger jellyfish, and sodium bicarbonate has been found to worsen mauve stinger jellyfish nematocyst discharge in vitro in another study.[11]  Although there are conflicting recommendations, use of alkaline or acidic solutions may possibly cause a worsening of the envenomation based on available literature and probably should be avoided.[3]

Though there are conflicting data and recommendations, the general recommendation for local care of mauve stinger jellyfish stings is first washing the area with seawater.  As removing the attached nematocyst may cause increased envenomation, any adherent jellyfish parts should gently be removed with gloves or a tweezer after sea water washing.[8,9]  They can also be scraped off with a seashell,[9] but scraping has been shown to potentially increase nematocyst discharge in some jellyfish species.[8]  If gloves are not available, adherent tentacles may be removed with bare fingers, which may only cause relatively harmless prickling, due to the thick palmar skin, but this is not a first choice.[15,16]  Icepacks can then be applied for 10-15 minutes with a cloth protecting the skin.[15]  Topical lidocaine is recommended as an option in jellyfish stings by the Red Cross to reduce pain[9] and has been found in several mauve stinger studies to inactivate the nematocysts[11,12], so that can be one treatment option prior to removing the attached jellyfish parts.  The maximal recommended lidocaine dose should not be exceeded to avoid toxicity.  

Over the counter medication can be used for pain and medical treatment possibly requiring hospitalization may be needed for more severe reactions.  For all jellyfish stings, a tetanus booster is recommended if not up to date.  Prophylactic antibiotics are typically not necessary. Antihistamines can be used for urticaria or allergic-type symptoms. [17] 

There have been some studies using proprietary formulations to treat purple mauve stinger jellyfish stings, but one positive study was authored by manufacturer employees, unblinded and had no control group. [6]  The other was an in vitro study which found 10% lidocaine and some compounds used in cosmetics also work as inhibitors of nematocyst discharge.  It was thought that due to its viscous consistency one of the compounds, butylene glycol, wraps around the tentacle to act as a physical barrier. [11] 

Prevention

Prevention of stings can be achieved by avoiding swimming in jellyfish infested waters, or use of a lycra whole body stinger suit.[1]   A repellent cream of octyl methoxycinnamate and zinc oxide, sold commercially in some countries has been demonstrated to reduce the severity of jellyfish stings as well as providing sunburn protection.[1]  Another commercial jellyfish sting inhibitor and sunblock, that contains octinoxate, titanium dioxide and multiple other ingredients has also been demonstrated to reduce sting severity from some species. [15,18,19]

Conclusions

Mauve stinger jellyfish stings are painful but not life threatening.  This year they were seen in increased numbers in New Jersey and New York State coastal waters.  The literature, as is typical with jellyfish research, is sometimes contradictory.  Avoidance of jellyfish when they are seen in the water is the best advice, but once stung, washing with seawater and gentle removal of attached parts of the jellyfish is recommended.  Acid and alkali solutions have in some studies shown to worsen the venom discharge from nematocysts and are probably best avoided.  Topical lidocaine may reduce pain and inactivate nematocysts.  Other products that have been tested may have some benefit, but the studies were either in vitro or were not of sufficient scientific quality.  

By Stuart M Caplen, MD